A Velytsky

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We study the zeros of the partition function in the complex β plane (Fisher's zeros) in SU(2) and SU(3) gluodynamics. We discuss their effects on the asymptotic behavior of the perturbative series for the average plaquette. We present new methods to infer the existence of these zeros in region of the complex β plane where MC reweighting is not reliable.(More)
We point out a general problem with the procedures commonly used to obtain improved actions from MCRG decimated configurations. Straightforward measurement of the couplings from the decimated configurations, by one of the known methods, can result into actions that do not correctly reproduce the physics on the undecimated lattice. This is because the(More)
We study the computation of the static quark potential under deci-mations in the Monte Carlo Renormalization Group (MCRG). Employing a multi-representation plaquette action, we find that fine-tuning the decimation prescription so that the MCRG equilibrium self-consistency condition is satisfied produces dramatic improvement at large distances. In(More)
We compare MC calculations of the density of states in SU(2) pure gauge theory with the weak and strong coupling expansions. Surprisingly, the range of validity of the two approximations overlap significantly, however the large order behavior of both expansions appear to be similar to the corresponding expansions of the plaquette. We discuss the(More)
We study the location of the partition function zeros in the complex β plane (Fisher's Zeros) for SU(2) lattice gauge theory on L 4 lattices. We discuss recent attempts to locate complex zeros for L = 4 and 6. We compare results obtained using various polynomial approximations of the logarithm of the density of states and a straightforward MC reweighting.(More)
We study charmonium correlators and spectral functions at zero and finite temperature using anisotropic lattices at several different lattice spacings. We find evidence for survival of 1S char-monia states at leas till 1.5T c and dissolution of 1P states at 1.16T c. c Copyright owned by the author(s) under the terms of the Creative Commons(More)
A new method of constructing a weak coupling expansion of two dimensional (2D) models with an unbroken continuous symmetry is developed. The method is based on an analogy with the abelian XY model, respects the Mermin-Wagner (MW) theorem and uses a link representation of the partition and correlation functions. An expansion of the free energy and of the(More)
We study the location of the partition function zeros in the complex β plane (Fisher's Zeros) for SU(2) lattice gauge theory on L 4 lattices. We discuss recent attempts to locate complex zeros for L = 4 and 6. We compare results obtained using various polynomial approximations of the logarithm of the density of states and a straightforward MC reweighting.(More)
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